1. Technical Field
The present disclosure relates to cavity filters, and more particularly relates to a tuning structure of a cavity filter.
2. Description of Related Art
Cavity filters are popular in mobile communications. Generally, a cavity filter includes a housing, a cover, a sliding plate, and a plurality of resonators. The housing defines an opening at a top of the housing. The resonators are securely received in the housing and the cover covers the opening. The housing includes a positioning portion adjacent to the opening. The sliding plate includes a plurality of tuning cells coated with a metal layer corresponding to the resonators. The sliding plate is movably disposed between the cover and the resonators, and slides on the positioning portion to adjust the frequency of the cavity filter. A gap is defined by the sliding plate related to the cover to avoid generating spark from the contact of the sliding plate and the cover. In use, the sliding plate slides relative to the cover and the resonators are driven by a driving device to adjust the resonating frequency of the cavity filter.
However, the sliding plate is prone to float upward while sliding due to the gap, so it is difficult to adjust the resonating frequency of the cavity filter accurately.
Therefore, there is room for improvement within the art.